Merge pull request 'Implement an instance-wide activitypub actor' (#4811) from algernon/forgejo:to-be-or-not-to-be into forgejo

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/4811
Reviewed-by: Gusted <gusted@noreply.codeberg.org>
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>

routers/api/v1/activitypub/actor.go

@@ -0,0 +1,83 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package activitypub
+
+import (
+	"net/http"
+
+	user_model "code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/activitypub"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/services/context"
+
+	ap "github.com/go-ap/activitypub"
+	"github.com/go-ap/jsonld"
+)
+
+// Actor function returns the instance's Actor
+func Actor(ctx *context.APIContext) {
+	// swagger:operation GET /activitypub/actor activitypub activitypubInstanceActor
+	// ---
+	// summary: Returns the instance's Actor
+	// produces:
+	// - application/json
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/ActivityPub"
+
+	link := user_model.APActorUserAPActorID()
+	actor := ap.ActorNew(ap.IRI(link), ap.ApplicationType)
+
+	actor.PreferredUsername = ap.NaturalLanguageValuesNew()
+	err := actor.PreferredUsername.Set("en", ap.Content(setting.Domain))
+	if err != nil {
+		ctx.ServerError("PreferredUsername.Set", err)
+		return
+	}
+
+	actor.URL = ap.IRI(setting.AppURL)
+
+	actor.Inbox = ap.IRI(link + "/inbox")
+	actor.Outbox = ap.IRI(link + "/outbox")
+
+	actor.PublicKey.ID = ap.IRI(link + "#main-key")
+	actor.PublicKey.Owner = ap.IRI(link)
+
+	publicKeyPem, err := activitypub.GetPublicKey(ctx, user_model.NewAPActorUser())
+	if err != nil {
+		ctx.ServerError("GetPublicKey", err)
+		return
+	}
+	actor.PublicKey.PublicKeyPem = publicKeyPem
+
+	binary, err := jsonld.WithContext(
+		jsonld.IRI(ap.ActivityBaseURI),
+		jsonld.IRI(ap.SecurityContextURI),
+	).Marshal(actor)
+	if err != nil {
+		ctx.ServerError("MarshalJSON", err)
+		return
+	}
+	ctx.Resp.Header().Add("Content-Type", activitypub.ActivityStreamsContentType)
+	ctx.Resp.WriteHeader(http.StatusOK)
+	if _, err = ctx.Resp.Write(binary); err != nil {
+		log.Error("write to resp err: %v", err)
+	}
+}
+
+// ActorInbox function handles the incoming data for the instance Actor
+func ActorInbox(ctx *context.APIContext) {
+	// swagger:operation POST /activitypub/actor/inbox activitypub activitypubInstanceActorInbox
+	// ---
+	// summary: Send to the inbox
+	// produces:
+	// - application/json
+	// responses:
+	//   "204":
+	//     "$ref": "#/responses/empty"
+
+	ctx.Status(http.StatusNoContent)
+}

routers/api/v1/api.go

@@ -805,6 +805,10 @@ func Routes() *web.Route {
 					m.Get("", activitypub.Person)
 					m.Post("/inbox", activitypub.ReqHTTPSignature(), activitypub.PersonInbox)
 				}, context.UserIDAssignmentAPI())
+				m.Group("/actor", func() {
+					m.Get("", activitypub.Actor)
+					m.Post("/inbox", activitypub.ActorInbox)
+				})
 				m.Group("/repository-id/{repository-id}", func() {
 					m.Get("", activitypub.Repository)
 					m.Post("/inbox",